Electric meter.



Patente'd Apr. 29, I902.

T. DUNCAN.

ELECTRIC METER.

(Application filed Aug. 28, 1899.)

2 Sheets$heet I.

(No Model.)

Fig. 2.

q/vblimeoaeo 5 vu va/14 4901 W a W. i w

MWM A gflb THE mmms PETERS C0,, WASHINGTON, u. c.

No. 698,652. Pat e nted Apr. 29, I902.

' T. DUNCAN.

ELECTRIC METER. (Application filed Aug. 28, 1899.; (No Model.) 2Sheets-Sheet 2.

wi lwvwow I E I g wve/wlioz GE. QM $1344 WWW %--W ms NORRIS PETERS cm,WASHINGYON, D. c.

UNITED STATES PATENT OFFICE.

THOMAS DUNCAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS & HALSKEELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRIC METER.

srnomxoarro v forming part of Letters Patent No. 698,652, dated April29, 1902.

' Application filed August 28, 1899. Serial No. 728,690. on model.)

To all whom. it may concern:

Be it known that I, THOMAS DUNCAN, of Chicago, in the. connty'of Cookand State of Illinois, have invented certain new and useful Improvementsin Electric Meters; (Case- No. 60,) of which the following is aspecification.

This invention relates to improvements in.

induction motor-meters for alternating-current work, and particularly tomeans for Ob? taining in such meters a magnetic field in quadrature withthe electromotive force which it represents.

The invention consists in the matters hereinafter described, andparticularly pointed outin the appended claims, and will-be fullyunderstood from the following detailed description of the constructionsillustrated in the accompanying drawings, in which- Figures 1, 3, and 4are diagrammatic views of meters embodying my invention. Fig. 2

. isa vector diagram of the essential current tions.

.coil between the terminals (1 and d of the.

main shunt-circuit. This resistance R is so connected as to'include moreor less of the turns D of the coil or coils l) and may be said tocomplete a subordinate circuit in which such included turns D are inseries with said resistance and with the volt field-coil 0.

As shown in Fig. 1, the impedance-coil D consists of two separatesections or coils each connected with one of theterminals c cv of thecoil 0, and the resistance R isconnected' to include a portion oftheturns of bothsec- In Fig. 3 the construction is similar, except thatthe'common core d of the impedance-coil is an annular ring instead of astraight bar. In this figure also an adjustable switch 1' is shown asprovided between one terminal of the resistance E and the adjacent coilD to permit more or less of the turns D of the latter to be cut in orout, as desired. In Fig. 4 the impedance-coil is a single coil, whichthe shunted resistance It connects directly to the terminal cl of themain shunt, to which latter the terminal a.

current to the coil 0,. as it wouldnatnrally be lagged by theimpedance-coil. The line E. represents the counter electromotive forceset up in the-turns D'by the inductive action ofthe current Fand theline f the current which this counter electromotive tends to set upinthe subordinate circuit formed by the resistance R, turns 1), and coilC. This current combines with the currentF to form the resultant currentF, which by proper proportioning andadjustment maybe made to lag theexact ninety degreesdesired.

I claim as my invention-=- 1. The combination, with the armature, se-

ries and volt field-coils, and impedance-coil in series with the voltfield-coil in a shuntcircuit across the line, of a resistance connectedin said shunt-circuit in parallel with the field-coil and including theturns of the impedance-coiL. v 1

2. The combination, with the armature, series and volt field-coils,and-impedance-coil in series with the volt field-coil'in a shuntcircuitacross the line, ofa resistance connected in said shunt-circuit inparallel with the volt field-coil and forming therewith a closed circuitincluding a portionof the turns of the impedance-coil.

3. The combination, with the armature, series and volt field-coils, andimpedance-coil in series with the volt field-coil in ashuntcircuitacross the line, ot a resistance connected in said shunt-circuit inparallel with the volt field-coil and forming therewith a closed circuitincluding a portion of the turns .of the impedance-coil, and means forvarying the number of the included turns.

zoo

4. Ihe co mbina tioh, with the arniatur; se

in shunt of one of the windings, including turns of'the impedance-coiland formingtherewith a closed. circuit, substantially as described.

In testimony that I claim the foregoing as myinvention I afiixnrysignature, inpresence of two subscribing witnesses, this 23d day ofAugust, A. D. 18.99; v y

i THOMAS DUNCAN.

Witnesses:

'- VWILLIAM F. MEYER,.

DAYTON N. PETTIT.

